I hate math I hate math I hate math I hate it I

If a and −a are numbers on the number line, which expression must give the distance between them? a) 0 b) a c) |2a| d) |a|

When a valve is open 281 gallons of water go through it in one hour the number of gallons that would go through in 94 hours is

Whoever gets this right gets the ! the half life of a soul smelling substance is 4 years. if you have 8 oz of this strange substance, how much of it will you have after 20 years? show work.